Switching to a lighter tripod definitely makes sense, especially if you're using it mainly for your spotting scope now. The Vortex Summit aluminum tripod is a solid choice. It's lightweight and offers good stability without breaking the bank. Another option you might consider is the Manfrotto BeFree Advanced. It's compact, lightweight, and sturdy, making it a great value for the price. For a bit more budget-friendly option, the Slik Sprint Pro II might be worth a look. It's lightweight and offers decent stability for a spotting scope.
Unfortunately, I can't provide direct links, but checking out local classifieds or online marketplaces like eBay or Craigslist might help you find a good deal on these tripods.
Happy hunting for the perfect tripod!